JP2599039B2 - Hydro balancer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrobalancer for receiving the weight of a spindle head such as a machining center, a gate boring machine and a portal drilling machine.

[0002]

2. Description of the Related Art As shown in FIG. 4, the weight of a spindle head is received by a hydrobalancer in order to reduce a load applied to a vertical positioning mechanism of the spindle head. That is, in a known horizontal machining center (not shown), a spindle head 1 vertically guided between columns 3 and bearing a horizontal spindle 2 is a feed screw rotatably supported by a servomotor 4 provided vertically on the columns 3. 5 for vertical movement. A hydrobalancer 7 is vertically fixed to the upper part of the column 3, and a piston rod 10 of a piston 9 fitted to a cylinder 8 is connected to the spindle head 1. Then, pressure oil is sent to the lower chamber of the cylinder 8 and receives the weight of the spindle head.

[0003]

When the spindle head is positioned and moved by the feed screw by the rotation of the servomotor, the balancer must always follow. Therefore, a hydraulic supply unit 11 for supplying a necessary amount of pressure oil to the balancer is attached. In order to satisfy the demand for high-speed positioning feed, a large amount of pressure oil needs to be supplied. For example, the weight of the spindle head 1 is 600 kg, and the cylinder area A of the hydrobalancer 7 is A =
Assuming 8.6 cm ² and a rapid traverse speed of 25 m / min, a thrust of 600 / 8.6 = 270 kg / cm ^{2 is} required, and the required pressure oil supply Q of the pump is 8.6 × 2500 =
21500 cc, that is, Q = 21.5 l / min. For this reason, the hydraulic unit becomes large and expensive. In addition, since a large amount of pressure oil flows, heat generation of the hydraulic unit also increases, and a rise in the oil temperature causes thermal deformation of the machine. For this reason, there is a problem that an oil cooler having a large cooling capacity is required as a preventive measure, and the cost is further increased.

The present invention has been made in view of the above-mentioned problems of the prior art, and generally, a tool is rapidly approached to a work and a position where cutting is started is fixed at a position slightly before the work surface. Set to position. When the rapid traverse is completed, the speed is switched to the deceleration of about 0.2 sec. Therefore, paying attention to the fact that the effective operation time of the thrust of the hydrobalancer should be adjusted to this time,
An object of the present invention is to provide a hydrobalancer which can be used with a small hydraulic source having a small flow rate.

[0005]

Means for Solving the Problems The present invention to achieve the above object, after the fast-forward in the upstroke of the vertical movement
A heavy-weight hydrobalancer to be decelerated,
The above weight is applied to the piston fitted to the cylinder of the
Piston lock having an engagement flange at the head connected to the object.
The cylinder is provided so that it can be slid
Pressure via relief pressure reducing valve that regulates oil pressure to lower chamber
Oil supply means, and the pressure oil supply amount of the pressure oil supply means
When the fast-lift of a heavy object rises,
As a small capacity to raise the piston with a delay
At the end of or immediately before
The piston rod engages and the piston moves upward as a unit.
The thrust is applied to a heavy object .

[0006] Also , fast-forwarding in the up stroke of the vertical movement.
A heavy-weight hydrobalancer that is decelerated after
Piston piston to be fitted to the hydrobalancer cylinder
An axial engaging portion is provided at a lower end of the ton rod, and the axial engaging portion is provided.
An engaging portion for engaging with the cylinder,
Pressure via relief pressure reducing valve that regulates oil pressure to lower chamber
Oil supply means, and the pressure oil supply amount of the pressure oil supply means
When the fast-moving of a heavy object rises and later than the rising of the heavy object
It becomes a small capacity that raises the piston and rises
At or immediately before the end of the rapid traverse state, the engaging portion of heavy
The piston rod is engaged with the axially
It is configured so that the direction thrust acts on a heavy object .

[0007] In addition, fast-forwarding during an ascending stroke that moves up and down.
A heavy hydrobalancer that decelerates after
The piston fitted to the cylinder of the balancer is
And the connection path between the upper and lower chambers of the piston.
A check valve that opens in the downward direction of the piston is provided,
Oil supply means in upper chamber and relief pressure reducing valve in lower chamber
Pressure oil supply means is provided, and the pressure oil supply means
It will be small enough to compensate for the oil shortage,
When a heavy object is rising and fast-forwarding, open the check valve to remove oil in the upper chamber.
Into the lower chamber and supply the piston with a slight supply of pressure oil to the lower chamber.
It is configured to apply upward thrust .

[0008]

According to the first and second aspects, the spindle head is rapidly advanced by the motor, while the piston has a small amount of oil supplied by the pressurized oil supply means, so the elevation is delayed, and the thrust does not act on the spindle head, and the rapid feed is performed. End of state In the deceleration range, the piston touches and a rising thrust acts. When descending, the spindle head descends while receiving the thrust of the piston.

According to a third aspect of the present invention, both the spindle head and the piston are raised by rapid movement of the motor. In this state, the check valve of the piston opens and the oil in the upper chamber flows into the lower chamber to fill the oil,
The thrust of the piston acts on the head of the spindle with a small amount of hydraulic oil supplied to the lower chamber. When descending, the check valve acts and the piston descends while receiving the weight of the spindle head.

[0010]

First Embodiment A description will be given based on FIG. 4 are denoted by the same reference numerals and description thereof is omitted. A piston rod 10 connected to the spindle head 1 passes through the center of the piston 9 and has a flange 10a formed at the upper end thereof. An O-ring 12 is interposed between the piston and the piston rod so as to prevent oil leakage. The upper chamber of the cylinder 8 has an air vent 8b.
A pressure oil supply port 8a is provided in the lower chamber, and is connected to the tank 13 via a hydraulic pump 14, and a relief pressure reducing valve 15 via a conduit 16. The spring pressure of the relief pressure-reducing valve 15 is adjusted so that the lifting force of the hydrobalancer 7 becomes an oil pressure at which a force slightly smaller than the own weight of the spindle head 1 is obtained.

For example, a rapid traverse stroke is 200 mm, a cutting feed speed is 600 m / min, that is, 10 mm / sec.
When the cutting speed is 5 mm and the air cutting stroke is 5 mm, the amount of oil required to catch up at the start of cutting is 8.6 cm.
² x 20.5 cm = 176.3 cc, and the time allowed for oiling is the rapid traverse speed v = 25 m / min of the spindle head.
Then, the time for sending the fast-forward stroke is 200 / (25)
000/60) = 0.48 sec, air cut time is 5
mm / 10 = 0.5 sec, rapid traverse deceleration time 0.2 s
ec, the total time is 0.48 + 0.2 + 0.5 =
1.18 sec, therefore the required discharge amount Q of the pump is Q = 17
6.3 / 1.18 = 149.4 cc / sec ≒ 9 liters / min.

The operation of this configuration will be described. First, at the time of spindle head ascending positioning, the feed screw 5 is rotated by the servo motor 4 in accordance with a command from the NC device, and the spindle head 1 is raised at a rapid traverse toward the command position. The piston rod 10 rises as the spindle head 1 rises, and the air in the upper chamber is
It is discharged to the atmosphere from b. The hydraulic pump 14 is also driven together with the drive of the servomotor 4, and the oil in the tank 13 is sent to the lower chamber of the cylinder 8 from the pipeline 16 and the pressure oil supply port 8 a via the relief pressure reducing valve 15.

In this case, since the oil supply flow rate of the hydraulic pump 14 is as described above, the amount of oil supplied to the lower chamber is small and the rise of the piston 9 is delayed with respect to the rise of the piston rod 10, The thrust of the piston 9 does not act on the spindle head 1 during the rapid traverse stroke, the deceleration stroke, and the air cut stroke of the cut. However, the spindle head 1 is in the rapid traverse state, that is, the rapid traverse stroke,
By the end of the air cut in the cutting stroke after the deceleration stroke, the piston 9 that has risen late catches up, and the upper end surface of the piston 9 is in close contact with the flange 10a of the piston rod 10,
The spindle head, which has been reduced in weight by the thrust of the hydrobalancer 7 working effectively and supporting its own weight, is accurately positioned at the cutting start position.

Next, at the time of spindle head lowering positioning, the servo motor 4 is reversed and the spindle head 1 is lowered via the feed screw 5, but the flange 10 of the piston rod 10 integrated with the spindle head 1
a is in contact with the piston 9 and the oil in the lower chamber of the cylinder 8 is pushed and discharged from the pressure oil supply port 8a. However, since the spring pressure of the relief pressure reducing valve 15 is adjusted to obtain an optimum pressure for receiving the weight of the spindle head 1, the spindle head 1 receives its own weight by the action of the hydrobalancer 7 and is accurately positioned.

[0015]

Second Embodiment A description will be given based on FIG. In the first embodiment, the piston rod 10 is connected to the spindle head 1, but the piston rod 10 is connected to the piston 9 and a lower end of the piston rod 10 is provided with a flange 10b. On the other hand, the spindle head 1 is provided with an engagement step portion 1a in which a deep hole in which the flange 10b is loosely mounted is formed and the diameter of the opening is reduced.

In this configuration, when the spindle head 1 is rapidly traversed by the servo motor 4, the spindle head precedes the piston rod 10, so that the piston 9 is delayed and catches up at the end of the air cut in the cutting stroke, so that the thrust of the piston moves to the spindle head. The operation is the same as in the first embodiment.

[0017]

Third Embodiment A description will be given based on FIG. 4 and FIG. 1 are denoted by the same reference numerals, and description thereof is also omitted. The piston 9 is provided with a check valve 18 communicating only from the upper chamber to the lower chamber of the cylinder 8. The spring 20 of the check valve 18 is weak enough to support the weight of the steel ball 19. The air hole 8b in the upper chamber is connected to the hydraulic tank 13 by a pipe 21 so that oil is also supplied to the upper chamber of the cylinder 8. The oil supply amount of the hydraulic pump 15 is small enough to cope with replenishment of oil leakage from the pipeline.

The operation of this configuration will be described. When the spindle head 1 is raised by the servomotor 4 when the spindle head is raised, the integral piston rod 10 and piston 9 are raised, and the lower chamber of the cylinder 8 is under negative pressure. Therefore, the steel ball 1 of the check valve 18
9 is pulled and the oil in the upper chamber flows into the lower chamber to replenish the oil.

Since the hydraulic pump 14 is in operation, if there is any oil leakage on the way, the oil is replenished, and the hydraulic pressure to the lower chamber is applied, but the oil is hardly supplied from the pipeline 16. When the spindle head descends, the check valve 18 is closed and the oil in the lower chamber is
The piston 9 is discharged under the condition regulated by 5 and the piston 9 descends while receiving its own weight of the spindle head 1. The upper chamber has a negative pressure, and oil is supplied from the oil tank 13 through the pipeline 21.

[0020]

As described above, the present invention has the following effects. The hydrobalancer according to claims 1 and 2 is:
The self-weight is not balanced while the fast-forward state is rising by the discharge amount of the pump. Further, in claim 3
The check valve opens while the piston rises and the upper chamber
The oil flows into the lower chamber and is filled with oil, so that the discharge amount of the pump of the pressurized oil supply means is small and the purpose can be achieved, the hydraulic unit can be reduced in size, and the cost can be reduced. . The discharge amount is 2 in the conventional hydraulic unit as in the embodiment.
What required 1.5 liters / min is sufficient at 9 liters / min, which is about 1 / 2.4. Since the heat generation amount is reduced due to the miniaturization of the hydraulic unit, the temperature rise of the oil is reduced, and the thermal deformation of the machine is suppressed. Further, since the temperature rise is low, a dedicated oil cooler is not required, and the cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a first explanatory view of an embodiment of a hydrobalancer according to the present invention.

FIG. 2 is a second explanatory view of the embodiment.

FIG. 3 is a third explanatory view of the embodiment.

FIG. 4 is an explanatory diagram of a conventional hydrobalancer.

[Explanation of symbols]

 Reference Signs List 1 spindle head 4 servo motor 7 hydrobalancer 8 cylinder 9 piston 10 piston rod 10a, 10b flange 14 hydraulic pump 15 relief pressure reducing valve 18 check valve

Claims (3)

(57) [Claims] 1. After a rapid traverse in an up-and-down stroke
A heavy-weight hydrobalancer to be decelerated,
The above weight is applied to the piston fitted to the cylinder of the
Piston lock having an engagement flange at the head connected to the object.
The cylinder is provided so that it can be slid
Pressure via relief pressure reducing valve that regulates oil pressure to lower chamber
Oil supply means, and the pressure oil supply amount of the pressure oil supply means
When the fast-lift of a heavy object rises,
As a small capacity to raise the piston with a delay
At the end of or immediately before
The piston rod engages and the piston moves upward as a unit.
A hydrobalancer configured to apply a thrust to a heavy object . 2. After a rapid traverse in the up stroke of the vertical movement.
A heavy-weight hydrobalancer to be decelerated,
Piston of the piston to be fitted to the cylinder of the draw balancer
An axial engaging portion is provided at the lower end of the rod, and is engaged with the axial engaging portion.
A mating engagement portion is provided on the heavy object, and the lower chamber of the cylinder is provided.
Oil supply via a relief pressure reducing valve that regulates oil pressure
Supply means, and the pressure oil supply amount of the pressure oil supply means is adjusted to the weight.
When the fast-moving object rises, the pi-
As a small capacity to raise the ston, fast forward
At the end of or immediately before the end of the
The piston engages with the axial engagement portion of the
A hydrobalancer configured to apply a thrust to a heavy object . 3. A rapid traverse in an ascending stroke that moves up and down.
A heavy-weight hydrobalancer to be decelerated afterward.
Make sure that the piston fitted to the lancer cylinder is
Connected to the body, and
A check valve that opens in the lowering direction of the ton
Oil supply means in the chamber and relief pressure reducing valve in the lower chamber
Pressure oil supply means is provided, and the pressure oil supply means
It is small enough to complement the foot,
When the object rises and fast-forwards, open the check valve to lower the oil in the upper chamber.
Upward to piston with small pressure oil supply to lower chamber
Characterized by applying a thrust
Idrobalancer.